1. Field of the Invention
This invention relates to an improved method of converting lower alcohols and related oxygenates either to gasoline boiling point range hydrocarbons or to olefin-enriched chemical feedstock.
2. Description of Prior Art
The application of fluidized catalyst techniques, developed particularly in the petroleum industry for effecting chemical reaction embodying the distribution of heat and/or the disposal of undesired heat, has long been accepted as a major processing tool of the industry. For example, fluidized catalyst techniques have been particularly useful for catalytic cracking of oil vapors to produce lower boiling products and regeneration of the catalyst used in such an operation. It has also been proposed to use the fluidized catalyst techniques, primarily for the disposal of generated heat, in the highly exothermic reactions of Fischer-Tropsch synthesis and the known Oxo process and in other such exothermic processes. In the fluidized catalyst operations previously developed, disposal of the reaction heat has been accomplished by many different techniques, for example by transfer of catalyst through cooling sections. Not only are these prior art catalyst techniques used for temperature control by addition and/or removal of heat, but they have also been found useful for maintaining selective conversions and extending the active life of the catalyst used in the process.
The conversion of lower alcohols, such as methanol, to intermediate ether products, e.g., dimethyl ether, followed by conversion of the ether product to one or a combination of products comprising olefins, paraffins, and/or aromatics has been the subject of several patents. Such patents include U.S. Pat. Nos. 3,480,408; 3,928,483; 3,931,349; 3,969,426; 3,998,898; 3,988,899; 4,013,732; 4,035,430; 4,044,061; 4,046,825; 4,052,479; 4,058,576; 4,062,905; 4,071,573; 4,076,761; 4,118,431 and 4,138,440, the entire contents of all of which are incorporated herein by reference.
In prior art processes conversion was usually carried out completely to maximize the production of C.sub.5.sup.+ gasoline boiling point range hydrocarbons.